Don’t have a scanner? Use a digital camera
Sometime in the past couple of years, I needed to scan a document and was lamenting the fact that I didn't have a scanner. And then it occurred to me (or maybe someone else suggested it, I'm not sure): for most of my purposes, a digital camera does exactly the same thing as a scanner, only faster and more conveniently.
If you need a high-quality artwork scan, then a digital camera probably isn't sufficient. And I don't know how feasible it is to do OCR on a photo from a digital camera.
But if you just need to create a human-readable computerized image of a page of text? Just snap a photo.
Maybe this approach is obvious. But I've seen other people run into the same conceptual barrier, being unable to do something because they didn't have a scanner but not realizing a photo from their cell-phone camera would work just as well, so I figured it was worth sharing the paradigm.
If you have an iPhone, you can go a step further and download the free Genius Scan app, which provides some extra tools to make photos even more like scanning.